During waning flood flows in gravel-bed streams, finegrained bedload sediment (sand and fine gravel) is commonly winnowed from zones of high shear stress, such as riffles, and deposited in pools, where it mantles an underlying coarse layer. As sediment load increases, more fine sediment becomes available to fill pools. The volume of fine sediment in pools can be measured by probing with a metal...

Field rainfall simulation experiments at two sites are used to partition sediment transport on unpaved roads into splash and hydraulic erosion components. Rain splash processes contributed 38–45% of total sediment output, with instantaneous contributions being variable throughout 60-min high-energy events. For lowand medium-magnitude rainstorms, splash erosion on roads is initially controlled b...

Oxygen microelectrodes were used to analyze the distribution of the diffusive boundary layer (DBL) at the sediment-water interface in relation to surface topography and flow velocity. The sediment, collected from saline ponds, was covered by a microbial mat that had high oxygen consumption rate and well-defined surface structure. Diffusion through the DBL constituted an important rate limitat...

Total Hg distributions and its speciation were determined in two sediment cores collected from the western continental marginal high of India. Total Hg content in the sediment was found to gradually increase (by approximately two times) towards the surface in both the cores. It was found that Hg was preferentially bound to sulfide under anoxic condition. However, redox-mediated reactions in the...

_____________________________ Introduction. ___________________________ Scope of work and available information,... Theory of sediment yield and transport__. Fine sediment.______________________ Splash, sheet, and rill erosion____ Environmental factors__ _ _______ Coarse sediment.____________________ Effect of velocity.__---__________ Effect of particle size_____________ Storm characteristics._...

The interaction between pollutants and sediment particles often occurs on the particle surface, so surface properties directly affect surface reaction. The physical and chemical processes occurring on sediment particle surfaces are microscopic processes and as such need to be studied from a microscopic perspective. In this study, field emission scanning electron microscopy (SEM) and energy disp...

Surface water and sediment on and near the Hanford Site are monitored to determine the potential impacts of Hanford-originated radiological and chemical contaminants to the public and to the aquatic environment. Surfacewater bodies included in routine surveillance are the Columbia River, riverbank springs, onsite ponds, and irrigation water at the Riverview irrigation canal. Sediment surveillan...

To assess the ca. 20-year polychlorinated biphenyl (PCB) contamination trends in Lake Hartwell, SC, sediment cores from the Twelve Mile Creek arm were collected in July 2004 at two sites (G30 and G33) first sampled in the mid-1980s. Congener-specific PCB data as a function of depth from the sediment-water interface for the 2004 sediment samples were compared to data obtained from 1987 and 1998 ...

gully erosion has an important role in fars province due to sediment production and enormous damages to land, roads and infrastructures. in this research, 15 gullies were selected to measure their morphometric characteristics. the length, depth, top and bottom width and volume of gully erosion were then measured. influential factors on the sediment production and gully development were analyzed...

The long-term goals are 1) to assess the role of small gas bubbles in shallow sandy coastal sediment for sediment geotechnical properties, the transport of solutes across the sediment-water interface and the biogeochemical processes in the sediment surface layer 2) to develop and apply an acoustic technique for the detection and quantification of small gas bubbles in sandy sediment at a high sp...